Devices such as intramedullary rods, bone nails, bone screws, plates, etc. may be affixed to a bone to repair or strengthen fractured or otherwise damaged or diseased bones, often by fixing two or more bones or bone pieces with respect to each other, in which case the device may be referred to as a fixation device. Such fixation devices share the load with the bone to support the bone as it heals. The fixation device may be further adapted to deliver medication or other fluids into bone.
For unthreaded, smooth-sided devices, secondary fixation devices such as screws may be used to rotationally fix the fixation device to the bone. These screws are generally oriented orthogonally with respect to the fixation device and pass through bores formed in the fixation device. A drill is used to form a passage in the bone, the passage extending through the bore in the fixation device. The drill bits used for such procedures are typically formed of a similar material to the fixation device itself, such as a stainless steel or titanium alloy or a material that is harder than the material from which the fixation device is formed.
If the drill is improperly oriented during the drilling procedure or if the drill bit is too large in diameter relative to the bore, the drill bit may contact a portion of the fixation device (e.g., the portion of the fixation device surrounding the bore) and cause scoring or other physical damage to the fixation device. Such physical damage can compromise the effectiveness of the fixation device, such as by physically weakening the fixation device in a high stress area or by affecting the delivery of medication or other fluids to the bone.